re scraping the coating off, i did it with a reversing ring to get CIF to work correctly with no camera fry up. you also have to take some off even with tubes with contacts unless they have a non coated face. this is a Jessops branded set showing where the coating needs removal (on all 3 tubes)

thanks Gary, used to think the same but after living here for forty odd years and seeing the huge drop in numbers we have now compared to when we first arrived i have a bit more sympathy for them

thanks for the comments. they are interesting to watch at the moment as they are in and out with nest building material, next it will be food for the babies and then they will be poking their heads out. the colours that come out on them when lit by the sun never fails to amaze me.

Derek, i think you will find using a Macro lens plus ext tubes will give a very narrow DOF no matter what aperture you use purely because of the high magnification which is why macro shooters now tend to use focus stacking to get sharpness all the way through the shot.
this is Nass's site , a lot of excellent information and help are in it including relevant links to what equipment, kit and methods he talks about. a very good read.
http://extreme-macro.co.uk/

could not resist these in the morning sun. taken with Tamron Adaptll 2 90mm f2.5 Macro lens

good set Derek, it is hard to get decent shots hand held at that magnification, well done. have found CIF a great help in that situation but i probably have older and shakier hands than you.

these were all shot using Sigma 10-20 f4-5.6, a Sigma 17-70 f2.8-4 then when that broke i picked up a Pentax 17-70 f4 . nearly all are small village churches with a couple of a bigger ones albeit in small villages
the majority are at 17mm and none are with the lens wide open. shot using tripod, remote shutter release and bracketed where i thought it was needed.

https://www.flickr.com/photos/haywagon200/16591804250/in/album-72157647886394224...

same lenses used for the externals as well, again 17mm seems to be the most used

https://www.flickr.com/photos/haywagon200/32669191792/in/album-72157671166059192...

hope this will help with your choice. used to own a 16-45 and always thought it a very good lens and only got rid of it to move to primes which i found did not suit me so back to variable lenses

thanks people, i did have shutter release set to AF as i use CIF quite a bit with macro but it still kept firing even when out of focus. it took a while for my old brain to twig the coating on the ring could be the problem

answered my own question and just purchased a genuine Pentax one in chrome, this will short out all contacts as the lens mount does.

having trouble getting this to work with a reversing ring, which is anodised black, the shutter releases when out of focus. do i need to scrape the coating off the ring to short certain contacts out to get it to work? it works fine with the lens attached (M 28mm f3.5) but this has a chrome mating face. any help much appreciated